Coming soon to a pond near you: air moving faster than the speed of sound

By Stephen Ornes, 00:00 AM February 3, 2010

Supersonic means faster than the speed of sound, which is about 760 miles per hour in air. That’s a speed limit that can be broken — by jets and bullets, for example, or by the space shuttle as it returns to Earth.

Now, a scientist named Stephan Gekle has found that you can make air move faster than the speed of sound by doing a simple little trick: throw a rock in a pond.

View video | As a disc representing a stone plunges into still water, it plows out a column of air. The column collaps...